My final Goal is to use state-machine model exported from a tool called BouML in M2M transformations, but my question here is about UML Editor.

The model, as quoted below, is compliant with http://schema.omg.org/spec/UML/2.1, which is not registered in my EMF models registry.
When I open the file with "UML model editor", it succeeds in viewing this model.

Question 1 : Why can it correctly view the model whereas the MModel it is compliant with is not registered as en EMF metamodel ?
Does it mean that UML tool don't rely on EMF ?